Tail recursion in Sacala

RecursionTest.scala

import org.scalatest.FunSuite

class RecursionTest extends FunSuite {

  case class Explosion(message: String) extends RuntimeException

  object Bomb {
    def tick(countdown: Int): Int = {
      println("hello")
      if (countdown == 0) throw new Explosion("BOOOOM!")
      else tick(countdown - 1)
    }
  }

  test("recursion") {
    Bomb tick(3)
  }
}

import scala.annotation.tailrec

class RecursionTest {
  @tailrec final def tick(countdown: Int): Int = {
    if (countdown == 0) throw new Exception("BOOOOM!")
    else tick(countdown - 1)
  }
}